I have spent some time reviewing content related to this topic, and will make an attempt at answering my own question in a rigorous manner such that it may benefit other users.
Note: Some relevant links were omitted from this post due to stackexchange restrictions on new-users.
Fair-use and the various forms of illegally obtaining/modifying content both fall under the exclusive subject-matter jurisdiction of federal courts. But, these two issues would likely be treated separately, as they represent civil and criminal cases, respectively.
Fair-use law is presented in Title 17 Chapter 1 Section 107 of the US Code. Fair-use provisions protect the use of copyright-protected works from claims of civil damages (Copyright Acts § 502 and 504) in specific circumstances. Whether a given instance of use should be considered fair can be decided only by a federal judge. However, the result of this determination has no bearing on a criminal case regarding the method of acquisition of a file. Some instances of copyright-infringement may also be treated criminally, but such cases (e.g. sale of illegally copied content) would be quite clearly in the realm of unfair use, and thus are not considered relevant to this question, except possibly as pertains to torrent piracy, especially in cases of sale.
Criminal consequences were set forth under the Digital Millennium Copyright Act (DMCA). Among other actions, this law criminalized the act of circumventing digital rights management (DRM) access controls. This includes ‘ripping’ DVDs. However, the DMCA explicitly provides some exemptions to its own rules, and a mechanism by which further exemptions may be created. Part of this mechanism requires that the Librarian of Congress issue exemptions from the prohibition against circumvention of access-control technology when it is shown that the technology had a substantial adverse effect on the non-infringing use of copyrighted works (i.e. fair use and other cases). These exemptions expire after three years from their effective date (most recently September 18, 2015) unless a case is made to the librarian, through the registrar of copyrights, to renew the exemptions.
However, there are some permanent exemptions, and suggestions for new permanent exemptions documented in
Title 17 Section 1201
III. C. Especially notable among these was “f. All Lawful or Fair Uses”, though this is currently just a noted suggestion.
Additionally, the U.S. Copyright Office and the Library of Congress renewed some of the previous temporary exemptions (see pages 17 and 22-25 of their final rule, 37 CFR Part 201 [Docket No. 2014-07]).
Thus, there is some variance in the legality of acquiring digital copies, even as applies to DVD ripping in particular. The aforementioned exemptions reveal that there are some cases in which considerations of fair-use have led to exemptions to the DMCA.
It is clear that fair use is intrinsically connected to the issues treated under the DMCA, but as illustrated above, they would likely be treated separately in a legal context.
- Will fair-use and source legality be determined separately in a court of law?
- Further, will a judicial determination that the content source (or method of acquisition) was illegal necessarily determine that usage was "unfair"?
ANSWER: No, this criminal determination would not lead to a civil determination of fairness. However, this other civil liabilities may still apply.
- Conversely, does fair-use ever justify the method of sourcing content (especially dvd-ripping)? This has been implied in responses elsewhere on stackexchange.
ANSWER: Sort-of. In some special cases, considerations of fair-use have lead to exemptions to DMCA restrictions.
Perhaps a relevant follow-up question would be: in the course of legal action pursuing the question of fair-use, can a court exercise a warrant over sources for content used, to determine if criminal liability under the DMCA applies?